LibJS: Implement Object.defineProperties()

Author: https://github.com/linusg
Commit: https://github.com/SerenityOS/serenity/commit/da8a35a79e1
Pull-request: https://github.com/SerenityOS/serenity/pull/6218
Reviewed-by: https://github.com/Lubrsi

Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h

@@ -95,6 +95,7 @@ namespace JS {
     P(count)                                 \
     P(countReset)                            \
     P(debug)                                 \
+    P(defineProperties)                      \
     P(defineProperty)                        \
     P(deleteProperty)                        \
     P(description)                           \

Userland/Libraries/LibJS/Runtime/Object.cpp

@@ -900,6 +900,49 @@ bool Object::define_native_property(const StringOrSymbol& property_name, AK::Fun
     return define_property(property_name, heap().allocate_without_global_object<NativeProperty>(move(getter), move(setter)), attribute);
 }
 
+// 20.1.2.3.1 ObjectDefineProperties, https://tc39.es/ecma262/#sec-objectdefineproperties
+void Object::define_properties(Value properties)
+{
+    auto& vm = this->vm();
+    auto* props = properties.to_object(global_object());
+    if (!props)
+        return;
+    auto keys = props->get_own_properties(PropertyKind::Key);
+    if (vm.exception())
+        return;
+    struct NameAndDescriptor {
+        PropertyName name;
+        PropertyDescriptor descriptor;
+    };
+    Vector<NameAndDescriptor> descriptors;
+    for (auto& key : keys) {
+        auto property_name = PropertyName::from_value(global_object(), key);
+        auto property_descriptor = props->get_own_property_descriptor(property_name);
+        if (property_descriptor.has_value() && property_descriptor->attributes.is_enumerable()) {
+            auto descriptor_object = props->get(property_name);
+            if (vm.exception())
+                return;
+            if (!descriptor_object.is_object()) {
+                vm.throw_exception<TypeError>(global_object(), ErrorType::NotAnObject, descriptor_object.to_string_without_side_effects());
+                return;
+            }
+            auto descriptor = PropertyDescriptor::from_dictionary(vm, descriptor_object.as_object());
+            if (vm.exception())
+                return;
+            descriptors.append({ property_name, descriptor });
+        }
+    }
+    for (auto& [name, descriptor] : descriptors) {
+        // FIXME: The spec has both of this handled by DefinePropertyOrThrow(O, P, desc).
+        //        We should invest some time in improving object property handling, it not being
+        //        super close to the spec makes this and other things unnecessarily complicated.
+        if (descriptor.is_accessor_descriptor())
+            define_accessor(name, descriptor.getter, descriptor.setter, descriptor.attributes);
+        else
+            define_property(name, descriptor.value, descriptor.attributes);
+    }
+}
+
 void Object::visit_edges(Cell::Visitor& visitor)
 {
     Cell::visit_edges(visitor);

Userland/Libraries/LibJS/Runtime/Object.h

@@ -115,6 +115,8 @@ public:
     bool define_native_function(const StringOrSymbol& property_name, AK::Function<Value(VM&, GlobalObject&)>, i32 length = 0, PropertyAttributes attributes = default_attributes);
     bool define_native_property(const StringOrSymbol& property_name, AK::Function<Value(VM&, GlobalObject&)> getter, AK::Function<void(VM&, GlobalObject&, Value)> setter, PropertyAttributes attributes = default_attributes);
 
+    void define_properties(Value properties);
+
     virtual bool delete_property(const PropertyName&);
 
     virtual bool is_array() const { return false; }

Userland/Libraries/LibJS/Runtime/ObjectConstructor.cpp

@@ -49,6 +49,7 @@ void ObjectConstructor::initialize(GlobalObject& global_object)
 
     u8 attr = Attribute::Writable | Attribute::Configurable;
     define_native_function(vm.names.defineProperty, define_property_, 3, attr);
+    define_native_function(vm.names.defineProperties, define_properties, 2, attr);
     define_native_function(vm.names.is, is, 2, attr);
     define_native_function(vm.names.getOwnPropertyDescriptor, get_own_property_descriptor, 2, attr);
     define_native_function(vm.names.getOwnPropertyNames, get_own_property_names, 1, attr);
@@ -250,6 +251,21 @@ JS_DEFINE_NATIVE_FUNCTION(ObjectConstructor::define_property_)
     return &object;
 }
 
+// 20.1.2.3 Object.defineProperties, https://tc39.es/ecma262/#sec-object.defineproperties
+JS_DEFINE_NATIVE_FUNCTION(ObjectConstructor::define_properties)
+{
+    if (!vm.argument(0).is_object()) {
+        vm.throw_exception<TypeError>(global_object, ErrorType::NotAnObject, "Object argument");
+        return {};
+    }
+    auto& object = vm.argument(0).as_object();
+    auto properties = vm.argument(1);
+    object.define_properties(properties);
+    if (vm.exception())
+        return {};
+    return &object;
+}
+
 JS_DEFINE_NATIVE_FUNCTION(ObjectConstructor::is)
 {
     return Value(same_value(vm.argument(0), vm.argument(1)));

Userland/Libraries/LibJS/Runtime/ObjectConstructor.h

@@ -46,6 +46,7 @@ private:
     virtual bool has_constructor() const override { return true; }
 
     JS_DECLARE_NATIVE_FUNCTION(define_property_);
+    JS_DECLARE_NATIVE_FUNCTION(define_properties);
     JS_DECLARE_NATIVE_FUNCTION(is);
     JS_DECLARE_NATIVE_FUNCTION(get_own_property_descriptor);
     JS_DECLARE_NATIVE_FUNCTION(get_own_property_names);

Userland/Libraries/LibJS/Tests/builtins/Object/Object.defineProperties.js

@@ -0,0 +1,57 @@
+test("length is 2", () => {
+    expect(Object.defineProperties).toHaveLength(2);
+});
+
+describe("errors", () => {
+    test("non-object argument", () => {
+        expect(() => Object.defineProperties(42, {})).toThrowWithMessage(
+            TypeError,
+            "Object argument is not an object"
+        );
+    });
+});
+
+describe("normal behavior", () => {
+    test("returns given object", () => {
+        const o = {};
+        expect(Object.defineProperties(o, {})).toBe(o);
+    });
+
+    test("defines given properties on object", () => {
+        const properties = {
+            foo: {
+                writable: true,
+                configurable: true,
+                value: "foo",
+            },
+            bar: {
+                enumerable: true,
+                value: "bar",
+            },
+            baz: {
+                get() {},
+                set() {},
+            },
+        };
+        const o = Object.defineProperties({}, properties);
+        expect(Object.getOwnPropertyNames(o)).toEqual(["foo", "bar", "baz"]);
+        expect(Object.getOwnPropertyDescriptor(o, "foo")).toEqual({
+            value: "foo",
+            writable: true,
+            enumerable: false,
+            configurable: true,
+        });
+        expect(Object.getOwnPropertyDescriptor(o, "bar")).toEqual({
+            value: "bar",
+            writable: false,
+            enumerable: true,
+            configurable: false,
+        });
+        expect(Object.getOwnPropertyDescriptor(o, "baz")).toEqual({
+            get: properties.baz.get,
+            set: properties.baz.set,
+            enumerable: false,
+            configurable: false,
+        });
+    });
+});